Document US 2006/0232265 A1, which is incorporated by reference herein, discloses an apparatus for measuring an electric current, wherein the apparatus comprises a Rogowski-Chattock coil and a circuit which is connected to the Rogowski-Chattock coil. In this case, the Rogowski-Chattock coil and the circuit each have a shield, wherein the two shields have a connection to ground. In this case, the shield of the Rogowski-Chattock coil prevents or reduces a capacitance acting between the Rogowski-Chattock coil and an electrical conductor to be measured.
Document US 2014/0340072 A1, which is incorporated by reference herein, discloses a Rogowski-Chattock coil which comprises a shield between itself and an electrical conductor to be measured by the Rogowski-Chattock coil. In this case, the shield prevents or reduces a capacitance acting between the Rogowski-Chattock coil and the electrical conductor.
Document 2012/0243140 A1, which is incorporated by reference herein, discloses a current measuring arrangement, wherein a conductor to be measured is surrounded by a coil, and a dielectric material is provided between the coil and the conductor.
In addition, document WO 2015/104189 A1, which is incorporated by reference herein, discloses a Rogowski-Chattock coil comprising two shields, wherein a dielectric material is provided between an electrical conductor to be measured and the Rogowski-Chattock coil, and an insulation is provided between the shields.
Furthermore, document US 2015/0293150 A1, which is incorporated by reference herein, discloses an electronic vehicle component comprising a current sensor, wherein the current sensor is protected against a magnetic field of a switch by a shield.
In the case of the apparatuses known from the prior art for measuring an electric current in an electrical conductor, a Rogowski-Chattock coil is often used, wherein the Rogowski-Chattock coil surrounds an electrical conductor to be measured in order to measure an electric current in the electrical conductor by way of a voltage which is induced in the Rogowski-Chattock coil. In electric vehicles and in the power electronics system of motor vehicles, there is an increasing incidence of very high voltages which can couple to the Rogowski-Chattock coil by way of their electric field and can thereby corrupt the measurement result of the Rogowski-Chattock coil. In order to prevent corruption of this kind, a shield at a fixed potential is often positioned between the Rogowski-Chattock coil and the electrical conductor to be measured, said shield preventing or reducing the electrical coupling. However, the use of a shield of this kind reduces the measurement bandwidth of the Rogowski-Chattock coil since the shield constitutes a capacitance and, respectively, acts like a capacitance on the Rogowski-Chattock coil.